Fertilizer and process for producing the same.



ran -ma s. wAsHBUn N, or NASHVILLE, TENNESSEE.

FERTILIZER AND nnocnss FOR rnonncmc THE SAME.

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To all whom it may concern Be it known that I, FRANK S. WAsHBUnN, a citizen of the United States, and a resident of Nashville, Tennessee, have invented .certain new and useful Improvements in'Fertilizers and Processes for Producing the Same, of which the followingis aspecification.

This invention relates to fertilizers containing mixtures of ammonia and phosa phoric acid and processes of producing the same, and has for its object totprovide a process which will be efficient and certain in operation as well as avproduct' which will be highly concentrated and will contain no acids which will be deleterious to the soil.

With these and other objects in view the invention ,consists' in the novel steps and combinations of steps constituting my process and in the novel product all as will be more fully hereinafter disclosed and particularly pointed out inthe claims. v

In carrying out my process, I take ordinary phosphate rock, such as is now used in the fertilizer industry, finely divide the same and treat it with sufiicient sulfuric acid (H SOQ to liberate substantially all the contained phosphoric acid, thus producing a crude solution of phosphoric acid which can be readily separated out in any suitable and well known manner, as by filtration from the insoluble residue. The crude phoshoric acid thus obtained will contain as impurities, soluble compounds containing iron and aluminum probably in the form of phosphates and sul ates, as well as small amounts of calcium sulfate.

An actual analysis of such a solution made on a commercial scale was found to contain the following a Fe" i 0.25% Fe"' A1 0,, 1.70%

' Ca Atrace; H 80 (free) 0.60%

In making the above solution the concentration of the sulfuric acid was not as high Specification of Letters Patent. Application and March 13, 1914. Serial No. 824,517.

containing. said mass to dryness Patentedduly 14, 1914..

as it mighthave been. In making other solutions I have used higher concentrations of sulfuric acid and of course obtained hlgher percentages of phosphoric acid and also larger percentages of the above impuritles. If I use a sufliciently concentrated sulfuric acid I can obtain 20% or higher of phosphoric acid and in such cases'the concentration of the impurities to the P 0 increasesin an accelerated ratio. i

I prefer to employ as high a concentration of sulfuric acid as commercial considerations will permit, for the greater percentages of lmpurities which follow are not injurious to'my process, while thegetting rid of the water or the lessening of the water in the solution on the other hand is very advantageous' as will presently appear. Nor does an excess of sulfuric acid in the solution interfere "with my processes will likewise appear below.

Having produced a solution of crude phosv phoric acid with as little water as commercial requirements willpermit, I next bring the same into contact with ammonia as b feeding this said crude solution into a tanli containing aqua ammonia charged with ammonla gas, whereupon I have, discovered that the reaction velocity will be so great that the insoluble products formed consisting of phosphates of aluminum,'iron and ammonia separate out in a gelatinous mass, and which mass will be found to be completely soluble in the standard ammonium citrate solutions used for determining the agricultural availability of phosphate compounds. The other constltutents of the solution consistingpr'in cipally above elatinous mass is also available as available as a plant food. ever,there is no need to .sep nous mass. from, the solut on, fore prefer to merely evaporate, the solution in any suitwhere'up'on, I have my new able manner.

he fo'r'mio'f a dry powder conproduct in t of ammoniumphosphate, of course, are available, as a plant food, and as. the

t aining as its essential ingredients ammonia and phosphoric acid in an available form to be used as a fertilizer.

It is a very important feature of my vention that the crude phosphoric acid solution is fedto the ammonia instead of the ammonia being fed to: the said crude solution.- For if the latter procedure is followed, ashas been heretofore proposed, there will result a series of products more or less insoluble in ammonium citrate, and therefore not available as a plant food. In fact by followinga reversal of my process as has between my process and the said-reversed process proposed by others, so far as I am able to explain, resides in the fact that when the crude solution is fed to the concentrated ammonia solution,-a small quantity of crude acid comes into contact with a large quantity of concentrated ammonia, and consequently a difl'erentseries of products follows from those resultingfrom the'feeding of a small quantity of concentrated ammonia solution to a large quantity of crude acid solution. In other words an important feature of my invention resides in the fact that I keep an excess of ammonia in contact with my crude phosphoric acid. It will thus be seen in fact that almost any process hy 'W-hich an excess'of ammonia is kept in contact with my crude phosphoric acid will produce my results, and in practice I prefer to feed-ammonia gas to. a tank containing-mono-ammonium phosphate until it is converted into di-ammon1um"phosphate, and then add my crudesolution of phosphoric acid until the said diammonium phosphate has been transformed back into the. mono form. Wher'eupo'n I remove a portion of the solution consistin largely of ammonium phosphate and containing the above gelatinous precipitate'to the evaporator, and again saturate the remaining mono solution until it again becomes diammoniuin [jwhereupon the pro'cess re P fit H f should be ebserved that the rod tained by my process 'is an 'almosfi'white amorphous powder whil'e'that obtained by the reversed procedure isof a greenishgray era gray color. It will be further observed that my product consists ofa water soluble constituent consistin of ammonium phosphate mixed with t e gelatinous constitu-- ents insoluble in water but citrate soluble and consisting of, the above metal phosphates of iron and aluminum which are likewise available as a plant food.

It is obvious that those skilled in the art may vary' the details of my invention without departin from the spirit thereof, and therefore I 0 not wish to be limited to the above disclosure except as may be required by the claims.

What I claim is 1. The process of rendering available I as a plant food the phosphoric acid "contained in phosphate rock which consists in treating said rock with sulfuric acid to obtainacrude solution of phosphoric acid and then feeding said crude solution to a second solution containing an excess of ammonia, substantially as described.

2. The process of renderin available as a plant food the phos horic acid contained in phosphate rock which consists in treating said rock with sulfuric acid to form a crude solution of phosphoric acid; and then feeding said crude solution to a solution containing di-ammonium phosphate, substantially asidescribed.

3. The process of rendering available as a plant food the phosphoric acid contained, in phosphate rock which consists in treating said rock with sulfuric acid to .form a crude solution of phosphoric acid; and then feeding said crude solution to a solution of mono-ammonium phosphate containing diammonium phosphate, substantially as described.

4. The herein described new fertilizer consisting substantially of an amorphous light colored material containing phosphates of ammonia and iron and substantially devoid of constituents unavailable as a plant food, substantially as described.

' 5. The herein described new fertilizer substantially devoid of constituents not available as a plantffood, consisting essentiallfl of ammonium phosphate mixed with sma phosphate, substantially as described.

quantities of aluminum and iron '6. The herein described new fertilizer v substantially devoid of constituents unavail able'as a plant food consisting essentially of ammonium phosphate mixed with a metal phosphate as an tially as described. m

7. The herein described new fertilizer substantially devoid of constituents =unavailable .as a plant food and consistingof an ammonium phosphate mixed with a water insoluble phosphate but which latter is citrate soluble, substantially as described.

8. The herein described new fertilizer .im'purity, substansubstantially devoid of constituents unavailable as a plant food consisting essentially of ammonium phosphate mixed with a metal phosphate, a part of the phosphoric acid being in a water soluble form and a part in a citrate soluble form, substantially as described.

In testimony whereof, I hereby sign my name this the 9th day of March, 1914, in the presence of two witnesses.

FRANK S. WASHBURN.

-Witnesses T. A. WITHERSPOON, Gr. M. SCHURMAN; 

